1. Field of the Invention
The present invention generally relates to a lock for an inswinging door which includes a retainer plate secured to the door jamb by elongated screws extending into and securely anchored to a wall stud or other secure anchor internally of a wall structure. The retaining plate is relatively thin and is positioned between the free edge of the inswinging door and the door jamb with an end edge thereof projecting inwardly beyond the inner surface of the door and door jamb for receiving a locking plate with the end of the retaining plate and locking plate including a unique interrelationship in order that the locking plate can be positioned on the retaining plate in a secure but readily assembled and releasable manner with a substantial portion of the locking plate overlying the inner surface of the door and another substantial portion of the locking plate overlying the door jamb, trim or adjacent wall surface. The locking plate is circular and has a central opening and a lateral passageway communicating therewith for assembly onto the inner end portion of the retaining plate and being rotatable into locking position. A tether chain is attached to a portion of the locking plate and to a wall bracket with upward force exerted on the tether chain causing rotational movement of the locking plate to automatically release the locking plate from the retaining plate thereby enabling rapid removal of the locking plate from its locking position in the event of an emergency and also enabling handicapped persons and young children to easily release the locking plate.
2. Description of the Prior Art
Many efforts have been made to provide a secure locking apparatus for access doors including various type of key operated locks, dead bolt latches and the like to enable property owners to lock a door as they leave the premises of a property and then gain access when returning by unlocking the door. In addition, various apparatuses have been provided to secure an inswinging door in a closed position when the occupants of a room or dwelling are within the room or dwelling. Some devices of this type include a slide bolt mounted on the inner surface of the door having an end which slides into a keeper mounted on the door frame. However, such devices are only as strong as the door frame and the door and can be easily rendered ineffective by inward force being exerted on the door. Various other efforts have been made to provide security for occupants of a room, apartment or the like by providing a bar which extends completely across the door and has the ends thereof connected to the door frame or wall structure such as disclosed in my prior U.S. Pat. No. 4,856,831 issued Aug. 15, 1989. Also, prior U.S. Pat. No. 5,098,192 issued Nov. 26, 1991 discloses a retaining plate attached to the door jamb with a generally cylindrical enlargement at its inner end together with a slotted locking plate that is positioned on the retaining plate and held in place by the enlargement on the inner end of the retaining plate. This patent and the prior art cited therein which are incorporated herein by reference thereto disclose various locking devices which are relevant to the present invention but are not pertinent to the specific unique structural and functional features of this invention.